Existing sound recording systems typically use two or three microphones to capture sound events produced by a sound source, e.g., a musical instrument. The captured sounds can be stored and subsequently played back. However, various drawbacks exist with these types of systems. These drawbacks include the inability to capture accurately three dimensional information concerning the sound and spatial variations within the sound (including full spectrum "directivity patterns"). This leads to an inability to accurately produce or reproduce sound based on the original sound event. A directivity pattern is the resultant sound field radiated by a sound source (or distribution of sound sources) as a function of frequency and observation position around the source (or source distribution). The possible variations in pressure amplitude and phase as the observation position is changed are due to the fact that different field values can result from the superposition of the contributions from all elementary sound sources at the field points. This is correspondingly due to the relative propagation distances to the observation location from each elementary source location, the wavelengths or frequencies of oscillation, and the relative amplitudes and phases of these elementary sources. It is the principle of superposition that gives rise to the radiation patterns characteristics of various vibrating bodies or source distributions. Since existing recording systems do not capture this 3-D information, this leads to an inability to accurately model, produce or reproduce 3-D sound radiation based on the original sound event.
On the playback side, prior systems typically use "Implosion Type" (IMT) sound fields. That is, they use two or more directional channels to create a "perimeter effect" sound field. The basic IMT method is "stereo," where a left and a right channel are used to attempt to create a spatial separation of sounds. More advanced IMT methods include surround sound technologies, some providing as many as five directional channels (left, center, right, rear left, rear right), which creates a more engulfing sound field than stereo. However, both are considered perimeter systems and fail to fully recreate original sounds. Perimeter systems typically depend on the listener being in a stationary position for maximum effect. Implosion techniques are not well suited for reproducing sounds that are essentially a point source, such as stationary sound sources (e.g., musical instruments, human voice, animal voice, etc.) that radiate sound in all or many directions.
Other drawbacks and disadvantages of the prior art also exist.